I've played the guitar for a little over 22 years now.
I'm 32 by the way.

I love the Knopfler thumb picking style, so I never play with a pick
But that is not something to start with.

Learn to use the pick and stum up and down to simple songs like
"Walk of life" on the brothers in arms album
It's in the key of E and also usees A and B cord.

So if you use these 3 cords you can become a rythme guitarist for MK
That's how I learned it.....and much later on started to do the lead stuff


Hope it helps